Shrimp net door



Aug. 24, 1965 J. M. JACKSON SHRIMP NET DOOR 3 Sheets-Sheet 1 Filed May 16, 1963 INVENTOR. I I. TAcxsoA/ TAMES ATTORNEYS 1965 J. M. JACKSON 3,201,889

SHRIMP NET DOOR Filed May 16, 1963 3 Sheets-Sheet 2 INVENTOR.

TAMEs M. TAcKso/v Aug. 4, 1965 J. M. JACKSON 3,201,889

' SHRIMP NET DOOR Filed May 16, 1963 3 Sheets-Sheet 3 [/60 INVENTOR. JAMES M. TAcKsoN AT TORNE Y5 United States Patent 3,201,889 SHRIMP NET DOOR James M. Jackson, Rte. 5, Box 237, Rose Dim Road, Savannah, Ga. Filed May 16, 1963, Ser. No. 280,867 9 Claims. (Cl. 43-9) This invention pertains to shrimp net doors or bottom otterboards.

An object of the invention is to provide a door arrangement which operates satisfactorily at depths of greater than about 400 feet and up to about 2400 feet. While royal red shrimp have been found between 400 and 2400 feet, and typically in substantial numbers between 1200 and 1400 for example, great difiiculty has been experienced in operating nets at these depths.

It is conjectured that the great length of the towing cables may interfere with or cause malfunction of the net doors. This invention is directed to doors and attachments for doors which will overcome the difiiculties encountered with long cables and at relatively great depths.

The novel features which are believed to be characteristic of this invention are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and method of operation, together with further objects and advantages thereof, may best be understood by reference to the following description taken in connection with the accompanying drawings, in which:

FIGURE 1 is a top plan view of two doors according to the invention represented in operative relation to a shrimp net and towing cables which are shown in fragment;

FIGURE 2 is an isometric view of one of the doors of FIGURE 1 on a much enlarged scale;

FIGURE 3 is a front elevational view of the door of FIGURE 2;

FIGURE 4 is an isometric view of a modified door construction embodying the invention;

FIGURE 5 is a front elevational view of the door of FIGURE 4;

FIGURE 6 is an isometric view of a door and door attachment, or a composite door arrangement according to a second modified embodiment of the invention; and

FIGURES 7 and 8 are a side elevational view and a front elevational view respectively of the attachment portion of the door arrangement of FIGURE 6.

With reference to FIGURE 1, net doors 1 and 2 are shown in operative position with trawl net 3 attached thereto. Each door is provided with a four-leg bridle, such as bridle 4 for door 1, and each bridle is connected at an apex ring such as ring 5 to a respective towing cable, such as cable 6.

Each of the doors 1 and 2 are, of course, identical, except that they are right and left hand, respectively, and door 1 is shown in detail in FIGURES 2 and 3. The door 1 comprises an upstanding operative main directing vane 7 carrying on its inner face 8 four bridle attachment rings 9, 10, 11 and 12, to which bridle arms 13, 14, 15 and 16 are respectively attached. The bridle apex ring 5 interconnects the several legs of bridle 4, and the leg lengths and the positions on the vane of rings 9 through 12 are so proportioned and arranged that the vane, when pulled through the water with a trawl net attached to net attachment rings 17 and 18 at the rear or trailing edge 19 of the vane, slants outwardly to pull open the net mouth and tilts outwardly to pull the net down. Specifically, vane 7 is arranged typically to point about eight to ten degrees to the right of the pulling vessel, and the vane inclines outwardly from its lower edge 20 to its upper edge 21 at an angle of about eight to ten degrees from the vertical.

Board 1 is weighted along its lower edge 20 such as by being formed of materials toward thelower edge which are heavier than those used elsewhere in theboard. Lower edge 20 curves upwardly gradually at 22 to meet front edge 23, whereby the board tends to ride overobstructions on the sea bottom. Attached along the upper edge 21 of the vane is an elongated cylindrical air tank 24;

preferably formed with conical or tapered ends as at 25 to reduce water resistance. The internal volume of the tank 24 is related to the total weight of the door assembly to provide almost sufiicient buoyancy to float the assembly. If, for example, the door assembly weighs about one ton, the tank 24 may have a capacity of about 20 to 22 cubic feet, and the net weight of the assembly When submerged would range from as much as 200 or 300 pounds to as little as zero or only a few pounds. Since the greater part of the weight of the door is concentrated near its lower edge, this weight and the buoyant force of the air tank cooperate to tend to hold the door upright. Preferably, the tank 24 is filled with air to a pressure substantially greater than atmospheric pressure, but somewhat less than the maximum pressure which may be imposed thereon when the door is submerged. If the door is to be used at about 1200 to 1500 feet, the air pressure in the tank might be between 300 and 500 pounds per square inch.

It has been found that, at depths greater than about 900 feet, the downward force resulting from the Weight of the towing cable attached to ring 5 of the bridle is such that the door, even when weighted near its lower edge and carrying an air tank, often turns on its side and does not properly control the net. In accord with the invention, a sea-bottom-engaging wing 26 is fixed to the vane 7 at the lower edge 20 thereof extending outwardly from the outer face 27 thereof at an angle to the face such that the wing will slide flat along the bottom when the vane is in its proper operating position. Since the vane is desirably inclined between about 6 and 10 degrees from the vertical, the wing should extend at an angle of between about and 84 degrees from face 27.

In the embodiment of FIGURES l-3, wing 26 is rigidly fixed in place at the desired angle by means of arms 28, 29 connecting between the rounded outer edge portion 30 of the wing and a portion 31 of the vane above its lower edge and preferably near its upper edge. While wing 26 is shown as solid and unbroken, it is not necessarily so, although it should have an unbroken rounded outer edge 30. If the wing is not solid, however, between the vane and edge 30, it is somewhat less suited to use on a muddy bottom. The wing preferably extends for the full length or nearly the full length of the vane. The width of the wing, as measured outwardly from the vane to the outer edge of the wing, should be not less than one-half of the height dimension of the vane but is, preferably, not greater than that dimension. For a vane 10 feet long and 4 feet high, a suitable wing 26 may be 8 or 9 feet long and 2 /2 feet wide, for example.

While the wing 26 is rigidly fixed to the vane in the embodiment of FIGURES l-3, FIGURES 4 and 5 show a modified embodiment wherein the door assembly comprises movable wings. As the door is lowered through the Water to reach the bottom, the wing of the first disclosed embodiment may cause undesirable fluttering, and there may also be instability of the boards as the net is raised. This difliculty is overcome by the more complicated constructions embodying movable wings.

The modified door 32 shown in FIGURES 4 and 5 includes a vane 33 having an :air tank 34 connected thereto for the purposes described above. The door 32 is a port 3/ 7 door for use in the po siti'on 2 as shown in FIGURE 1 and, accordingly, hasa bridle 35 on its inner or'star "with the vane 33 inclined outwardly .between'about 6 and degrees from the vertical. As seen in FIGURE 5,

of the vane. A pair of bracing and operating arms is pivotally connected to each of wings 37 and 38, arms'40 and 41 being angle of between80 and 84 degrees to the outer face39 connected by pivots 42 and'43 to wing 37,and arm 44 being connected by pivot 45 to wing 38. Asecond arm 46 is similarly'connected to wing 38. v The inner ends of the arms are, in turn, connected to piston rods of hydraulic cylinders. .More particularly, arms 40 and 44 meet at their inner ends at 47 andare there connected to piston rod 48 of hydraulic cylinder 49. Asimilar con- 10' 'the outwardly extending wing 38 when extended is at an a 4 and thus to cause cylinders 75 and 76 to selectively extend and retract their respective piston rods .77' and 78. Extension of these rods, as in FIGURES 4 and 5, will cause the wings toswingjup into retracted positions, while retraction of the rods'extends the wings.

Electrical connections 79 extend from the batteries and switch to motor 71 while hydraulic connections 80' and 81 interconnect the pump and cylinders. An hydraulic reservoir 82 is provided in connection with therpump. It'will be understood that, in. applying this system to the arrangement of FIGS. 4 and 5, cylinders 75 and 76 correspond tocylinders 49 and 50,that rods 77 and 78 correspond to rod 48 and the rod for cylinder 50, and

, that arms 66, 64 and 65 correspond to arms 44, 40 and nection is made between arms 41 and 46 to the pistonrod a of cylinder 50. a. a e

The cylinders 49 and 50 are disposed alignedly in vane 33, such as in cavities 51,52 thereof. It will be noted from FIGURE 5 that the arms 44 and 46 are pivoted,

as at 45, to wing'38 slightly'further from hinge 53, which connects the wing to the vane, than are pivots 42 and 43 41; Such hydraulic systems operated by connection to a reversible motor, and suchremote control systems for sition. 'Thusvane'56, being intended to position the starboard side of the net mouth, in'position for board 1 in FIGURE 1 is directed to starboard of the towing vessel I and, because of the hinge inclination, inclines outwardly ing raised or lowered in the water, and may be extended into the full line operative position while the net is being trawled on the sea bottom; During retraction and ex- If vane 33.is four feet highgwings s7 and 38 would be at least two feet in width and would be preferably approximately 3 or 4 feet wide. The total span of the wings when extended being 6 or 8 feet for a-41foot high board, the stabilityof the'board on the sea-bottom very good, the total weight of the wings having the tendency to maintain theboard upright and'guardingagainst inward as well as outward tipping over of the vane. i

The board of FIGURES 4 and 5 is preferably provided with a cable bridle rather than chains,thereby to mini-1 mize interference with wing 37 and its operating mecha nism. Rings 55 areprovided for connection to'the net; 7

The assembly shownin'FIGURES'6, 7 and 8 includes a door member 56 articulated by means of an outstand toward its'upper-edg'e while'vane 58 remains vertical.

An air' tank 85 is preferably "connected to vane 58 andthe. vane is preferably weighted, such as by the weight of batteries 69 and motor 71, toward its lower edge all asdescribed hereinabovein connection with the other embodiment. f

The wings attached to vane 58 stabilize the vane, while along the bottom.

In those instances in which only one outwardly extending wing is found-to'be'sufiicient, the inwardly exface and a position vention have been shown and described by way of illustration, many modifications'will'occur to those skilled in the art' and it is, therefore, desired that it be understood that it is intended in the appended claims to cover all such modificationsas' fallwithin' the true spirit and scope '1 1. A shrimpfnet door adapted for trawling at depths ing hinge 57 tea-substantially vertical'trailing vane 58,

there being two wings 59 and 60 hinged 'by hinges 61' and 62, respectively, to the lower edge 63'of vane 58.

The wings 59 and 60 are operated by arms including arms 64, 65, 66 each connected by a pivot, such as piv-s ots 67, 68 'to the wings, in this case equidistantly fro'm j therefor may be. the same for the arrangement of FIG-1 URES 6-8 as for that. of FIGURES4 andS. Housed within vane 58 are a set of batteries 69 connected through 0 a switch 70 to a motor 71 whichis operatively connected to pump 72 Switch 70 is controlled by an electric cable 73 which extends along towing cable 74 to the, towing vessel, and the switch is operable thereby into forward and reverse directions to operate motor71 and hydraulic f pump '72 in respective forward and reverse directions greater than 400 feet comprising an upstanding vane, a towing bridle attached to. theinner face of the vane,

- said vanehaving alower'edge adaptedto slide along the sea bottom; anda bottomengaging stabilizing wing extendingoutwardly'from said'lower edge beyond the outer face of the .vane a distance'equal toat least substantially one'half of the, height'dimension of the vane, said wing being disposedat an angle of between substantially and 'degrees from the outerface and being adapted'to slide along the sea bottom and to prevent tipping over of the vane, from 'the weight of the" towing cable.

7 2; A shrimp net door assembly for trawling at depths greater'than 400 feet comprising a main directing .vane member having a bridle connected thereto operative to direct and incline said vane 'ina predetermined outward direction with respect 'to thetowing vessel andtilted outwardly from the vertical thereby to pull downwardly and outwardly on the portion of the net door connected thereto, said vane member having a lower edge and an outer face facing generally in said predetermined direction, said'rnember beingarranged to skid along'thesea bottom on its saidlower. edge, a horizontal wing having an inner edge, andimeans connecting said wing at its inneredgej to said vane member and for retaining said Wing at an angle of between about 80 and 84 degrees with respect to said vane and extending in said outward direction from its said inner edge.

3. A shrimp net door assembly for trawling at depths greater than 400 feet comprising a main directing vane member having a bridle connected thereto operative to direct and incline said vane in a predetermined outward direction with respect to the towing vessel and tilted outwardly from the vertical thereby to pull downwardly and outwardly on the portion of the net door connected thereto, said vane member having a lower edge and an outer face facing generally in said predetermined direction, said member being arranged to skid along the sea bottom on its said lower edge, a horizontal wing having an inner edge, hinge means connecting said wing at its inner edge to said vane member and means for retaining said wing at an angle of between about 80 and 84 degrees with respect to said vane and extending in said outward direction from its said inner edge, said last means being selectively operable to swing said Wing upwardly on its said hinge connection into a generally upright retracted position.

4. A shrimp net door assembly comprising a main directing vane member having a lower edge adapted to skid on the sea bottom, a trailing edge, an inner face having a towing bridle extending inwardly therefrom and having an outwardly facing face, said member being adapted and arranged to assume a position when towed directed outwardly from the towing vessel and inclined outwardly from the vertical thereby to pull downwardly in the water, a trailing vane member hingedly connected to said main vane member and assuming an upright position when said main vane is so directed and outwardly inclined, and a wing extending outwardly from said trailing vane for sliding on the sea bottom and operative to support said vane members against tipping over outwardly under the influence of the weight of the towing cable.

5. The combination according to claim 4 wherein said trailing vane member further comprises an inwardly extending wing to support said vanes against tipping over inwardly and wherein means are provided for selectively retracting said wingsdnto inoperative positions generally parallel to said trailing vane. g

6. The combination according to claim 4 wherein remote controlled hydraulic means are provided on said trailing vane member operative to retract said wing into a position generally parallel to said trailing vane member.

7. The combination according to claim 2 and a sec ond horizontal wing having an outer edge and means connecting said second wing at its said outer edge to said vane member and for retaining said second Wing at an angle of between about 96 and degrees with respect to'said vane member and extending inwardly from its outer edge in a direction opposite to said outward direction.

8. The combination according to claim 1 and a buoyancy tank connected to and overlying said vane.

9. The combination according to claim 4 and an elongated buoyancy tank connected to, overlying and extending generally horizontally and parallel to said trailing vane member.

References Cited by the Examiner UNITED STATES PATENTS 2,062,718 12/36 Kallberg 4343.13 2,816,385 12/57 Luketa 439 3,023,537 3/62 Madson 4343.13

FOREIGN PATENTS 92,476 9/58 Norway.

ABRAHAM G. STONE, Primary Examiner.

P. RAY CHAPPELL, Examiner. 

1. A SHRIMP NET DOOR ADAPTED FOR TRAWLING AT DEPTHS GREATER THAN 400 FEET COMPRISING AN UPSTANDING VANE, A TOWING BRIDLE ATTACHED TO THE INNER FACE OF THE VANE, SAID VANE HAVING A LOWER EDGE ADAPTED TO SLIDE ALONG THE SEA BOTTOM, AND A BOTTOM-ENGAGING STABILIZING WING EXTENDING OUTWARDLY FROM SAID LOWER EDGE BEYOND THE OUTER FACE OF THE VANE A DISTANCE EQUAL TO AT LEAST SUBSTANTIALLY ONE HALF OF THE HEIGHT DIMENSION OF THE VANE, SAID WING BEING DISPOSED AT AN ANGLE OF BETWEEN SUBSTANTIALLY 80 